High surface area cathode assembly, system including the assembly, and method of using same

Abstract

A cathode assembly, a system including the cathode assembly, and method of using the assembly and system are disclosed. The cathode assembly includes high surface area material to allow efficient recovery of metal at reduced current densities at the cathode, which allows increased rates of metal recovery to be obtained, while maintaining desired properties of the electrowon metal.

What is claimed is: 
     
         1 . A high surface area cathode assembly for electrowinning metal from solution, the cathode assembly comprising:
 a hanger bar;   a high surface area material in contact with the hanger bar, the high surface area material having a surface area to volume ratio of about 0.05 ft 2 /in 3  to about 10 ft 2 /in 3 ; and   a container about at least a portion of the high surface area material.   
     
     
         2 . The high surface area cathode assembly of  claim 1 , wherein the high surface area material comprises material selected from the group consisting of metal hair wire, metal wool, metal fabric, metal foam, and conductive polymers. 
     
     
         3 . The high surface area cathode assembly of  claim 2 , wherein the high surface area material comprises at least one of a copper mesh, a copper wool, a copper fabric, a copper foam, and a copper hair wire. 
     
     
         4 . The high surface area cathode assembly of  claim 1 , wherein the surface area to volume ratio is about 0.1 ft 2 /in 3  to about 5 ft 2 /in 3 . 
     
     
         5 . The high surface area cathode assembly of  claim 1 , wherein the hanger bar comprises material selected from the group consisting of copper, copper alloy, copper aluminum alloys, aluminum, stainless steel, titanium, gold, and combinations thereof. 
     
     
         6 . The high surface area cathode assembly of  claim 1 , wherein the container comprises a material selected from the group consisting of polyethylene, polystyrene, polyvinyl chloride, and polytetrafluoroethylene. 
     
     
         7 . The high surface area cathode assembly of  claim 1 , wherein the container is a flow-through container comprising a plurality of voids and an open area of about 20% to about 80%. 
     
     
         8 . The high surface area cathode assembly of  claim 1 , further comprising a connecting element coupled to the container and the hanger bar. 
     
     
         9 . The high surface area cathode assembly of  claim 1 , further comprising a conductive element. 
     
     
         10 . The high surface area cathode assembly of  claim 9 , wherein the conductive element comprises at least one conductive rod. 
     
     
         11 . The high surface area cathode assembly of  claim 9 , wherein the conductive element comprises a metal sheet. 
     
     
         12 . The high surface area cathode assembly of  claim 9 , wherein the conductive element comprises material selected from the group consisting of copper, copper alloy, copper aluminum alloys, aluminum, stainless steel, titanium, gold, and combinations thereof. 
     
     
         13 . A system for electrolytic recovery of metal, the system comprising:
 an anode assembly;   a high surface area cathode assembly comprising a hanger bar, a high surface area material, the high surface area material having a surface area to volume ratio of about 0.05 ft 2 /in 3  to about 10 ft 2 /in 3 , and a container about at least a portion of the high surface area material; and   an electrolyte solution between the anode assembly and the cathode assembly; and   a tank containing the electrolyte solution.   
     
     
         14 . The system for electrolytic recovery of metal of  claim 13 , wherein the electrolyte solution comprises pregnant leach solution. 
     
     
         15 . The system for electrolytic recovery of metal of  claim 13 , wherein the electrolyte solution further comprises iron ions. 
     
     
         16 . The system for electrolytic recovery of metal of  claim 13 , wherein the system is a portable system and is placed near a source of the electrolyte solution. 
     
     
         17 . The system for electrolytic recovery of metal of  claim 13 , wherein a portion of the anode assembly and a portion of the cathode assembly are in direct contact. 
     
     
         18 . The system for electrolytic recovery of metal of  claim 13 , wherein the cathode assembly further comprises a conductor element coupled to the hanger bar. 
     
     
         19 . The system for electrolytic recovery of metal of  claim 13 , wherein the electrolyte solution comprises a Cu/Fe 3+  ratio of about 2 to about 6. 
     
     
         20 . The system for electrolytic recovery of metal of  claim 13 , wherein the electrolyte solution comprises a Fe 2+ /Fe 3+  ratio of about 2 to about 8. 
     
     
         21 . The system for electrolytic recovery of metal of  claim 13 , wherein the high surface area material comprises at least one of a copper mesh, a copper wool, a copper fabric, a copper foam, and a copper hair wire. 
     
     
         22 . The system for electrolytic recovery of metal of  claim 13 , wherein the cathode assembly further comprises a connecting element coupled to the hanger bar and the container. 
     
     
         23 . The system for electrolytic recovery of metal of  claim 13 , wherein metal ions are recovered from the electrolyte solution in the form of metal powder. 
     
     
         24 . The system for electrolytic recovery of metal of  claim 23 , wherein the metal powder is self-harvested from the cathode assembly. 
     
     
         25 . A method of recovering metal from an electrolyte solution, the method comprising the steps of:
 providing an electrolyte solution;   electrowinning metal from the electrolyte solution using a high surface area cathode assembly having high surface area material with a surface area to volume ratio of about 0.05 ft 2 /in 3  to about 10 ft 2 /in 3 ; and   harvesting the metal in the form of metal powder.   
     
     
         26 . The method of recovering metal from an electrolyte solution of  claim 25 , wherein the step of electrowinning is performed at a constant voltage. 
     
     
         27 . The method of recovering metal from an electrolyte solution of  claim 25 , wherein the electrolyte solution comprises one of a recycled solution, bleed solution, remediation solution, waste water solution, or acid mine drainage stream. 
     
     
         28 . The method of recovering metal from an electrolyte solution of  claim 25 , wherein the electrolyte solution contains between 0.1 g/l and 2.5 g/l of metal ions. 
     
     
         29 . The method of recovering metal from an electrolyte solution of  claim 25 , wherein the step of harvesting the metal in the form of metal powder comprises one of self-harvesting or dynamic harvesting.